Generally, currently used methods of preparing beverages consist in preparation of sugar syrup and blending of various types of raw materials (juices, extracts, water, flavoring agents etc.). In manufacturing kvass, beer, and honey beverages, the fermentation of prepared beverage bases is used followed by filtration, and if necessary hereafter by ripening of the obtained beverage or beverage base [Digests of recipes for non-alcoholic beverages, kvass from the bread raw materials. Moscow, 1983].
A method for making a non-alcoholic beverage by mixing sugar, kombucha concentrate, water-soluble melanin, water-alcohol solution of melissa with water in the presence of carbon dioxide and beverage ripening at temperature 7-10° C. is known (Patent RU 2210952). “Tea fungus” (Kombucha; Japanese fungus) represents a symbiosis of yeast and acetic-acid bacterium, which forms a film at the surface of the sweet tea infusion. The yeast fermenting sugar promote to the formation of a small amount of alcohol and carbon dioxide, and the acetic-acid bacteria ferment sugar with the release of acetic acid, consequently the obtained fluid (tea kvass) acquires a sweet-and-sour taste and is slightly carbonated [Great Soviet Encyclopedia (.C..), 1978, Moscow, Sovetskaia Entsiklopediya].
Patent RU No. 2153816 describes a beverage and a method for manufacturing for this beverage and for the culture medium to manufacture the beverage based on growing the tea-fungus biomass (zooglea) in a tea infusion with a sugar-containing product. A culture fluid obtained as a result of incubation of tea fungus zooglea under aerobic conditions in a nutritional sugar-containing medium followed by incubation under anaerobic conditions at a temperature from 12 to 40° C. during from 2 to 150 days, is used for preparing a beverage base. The base consists of the culture fluid and of a tea extract with a sugar-containing product. The base is ripened under anaerobic conditions, that is accompanied with a decrease of a dry solids weight ratio. According to a method of the invention biological activity of beverages depends on the incubation time. One of the shortages of the known method is a long duration of obtaining a beverage having the highest biological activity.
There is a known method for making a fruit-bread kvass, said method comprising using a yeast culture and obtaining a beverage enriched with useful substances compared to a common kvass due to adding fruit juices (RU 2337592), as well as a method for making an alcohol-free beverage, which comprises using a tea fungus culture and obtaining a pear-tasted beverage due to using fruit wastes as substrates (SU 1477364).
Patent RU 2337592 describes a method for beverage preparing based on the use of tea fungus in fermentation of tea and other sugar-containing products by gradual fermenting comprising pre-fermenting these sugar-containing products with the use of a yeast culture, other than a tea fungus culture, and then fermenting with the use of a tea fungus culture. A method for making a beverage having a biological activity includes the fermentation of a sugar-containing fluid in the presence of a tea fungus culture, the said method including initial fermenting a sugar-containing fluid with the use of another yeast culture during a period from 1 hour to 14 days at a temperature from 20 to 40 degrees, and the fermentation in the presence of a tea fungus culture is carried out during a time period from 10 hours to 30 days. The beverage should be desirably clarified at a temperature of not more than 15° C. A sugar-containing fluid obtained by mixing water and sugar or jam or honey is used. Also, a sugar-containing fluid with addition of a fruit juice is used.
Initial fermentation of a sugar-containing fluid with the use of a yeast culture (baker's yeast, or wine yeast, or other yeast cultures), followed by the repeat fermentation in the presence of a tea fungus culture produces a beverage, which is free of yeast aftertaste and of ‘dryness’ native to the traditional kvass.
Patent RU228012 describes a beverage preparing method including the fermentation of a sugar-containing water solution with addition of a tea fungus under aerobic conditions and its filtration, before obtaining the sugar-containing water solution the preliminary filtered and disinfected water being processed with natural minerals (such as chalcedony, Cambay stone, or quartz) by adding minerals to water and maintaining them in the solution during the whole fermentation process. The fermentation is carried out in three stages during 28-24 days at stepdown decrease of temperature from 32-30° C. to 28-25°. The persistence of minerals in water promotes to a positive growth of tea fungus microbial culture and prevents the growth of foreign microorganisms that do not belong to the natural symbiotic composition of tea fungus.
Patent RU2280394 describes compositions based on a combination of fermentation products of tea fungus (symbiosis of yeast and acetic acid bacteria) and chaga mushroom, which are obtained by the fermentation of a blend of a sugar-containing substance, tea fungus culture fluid and chaga mushroom extract (RU2280394). The fermented blend is additionally ripened under anaerobic conditions and/or at a temperature of not more than 10° C. Compositions are also obtained, which include a sugar-containing component, tea fungus zooglea and chaga mushroom extract by mixing a preliminary fermented composition consisting of sugar, tea fungus culture and chaga mushroom extract by fermenting the obtained mixture, kvass being used as a preliminary fermented composition.
A method for preparing a tea fungus zooglea has been described, which includes mixing a tea fungus culture with sugar and fluid, other than tea, followed by and fermenting the obtained mixture, a fruit or berry juice being potentially used as a fluid. So tea fungus zooglea was obtained by adding a tea fungus culture into a solution of blackcurrant juice. A solid fraction of the obtained zooglea was used as an additive for imitation of dry fruits in bakery manufacturing (a microbial depressing effect was achieved simultaneously for bakery products). The end fermentation of kvass wort, fermented with the use of common yeast cultures (bakery yeast), based on the tea fungus culture, allowed to obtain a beverage, similar to kvass but having a less degree of foaminess and more acid flavor.
However, microorganisms forming a tea fungus consortium, which are used for obtaining beverages in described methods, have not been identified, and moreover, compositions of consortia in various geographic areas are different, consequently, products have also different compositions and its standardization is very problematic.
Patent RU 2165711 describes the use of tea fungus microflora Medusomyces gisevii in a method for preparing a starter culture for fermented milk products. Skim milk is pasteurized, cooled to the temperature of fermentation, then tea fungus microflora Medusomyces gisevii is added directly into milk in the ratio tea fungus:milk 1:30, fermented at 20-24° C. during 20-28 hours to the formation of a clot with acidity of 95-100° T. The obtained starter culture is used for manufacturing fermented milk products.
Patent RU2081911 describes a consortium of yeast and bacteria and a method for making a low-alcoholic beverage on its base. The consortium of yeast and bacteria includes Saccharomyces mandshuricus, Hausemaspora sp, Torulopsis globosa, Torulopsis sp, Saccharomyces Ludwigii, Saccharomyces lactis, Acetobacter xylinum, Acetobacter aceti, and Gluconobacter subaxydans and produces a complex of vitamins, organic acids, enzymes and cellulose. The method provides for making a low-alcoholic beverage with the use of a consortium of yeast and bacteria by means of fermentation of raw material blend, consisting of a carbohydrate-containing substrate and a nitrogen source at a temperature 24-32° C. during 4-5 days. A liquid fraction is separated by filtration or centrifugation. The liquid fraction is used as a low-alcoholic tonic drink.
Disadvantage of the known method is that the used consortium is a inseparable community of yeast and bacteria, that does not allow to use valuable properties of separate microorganisms for creating a greater variety of products and improving its taste and health-giving potential as well as optimizing its manufacturing methods and developing integrated technologies of preparing tea fungus cultures, kombucha concentrates, and various beverages based on tea fungus cultures and concentrates.
Moreover, the efficacy of the known methods of preparing beverages with the use of tea fungus remains fairly low due to simultaneous formation of zooglea. Thus, the development of industrial production methods that allow significant speeding up improving the production process of beverages having various tastes and health-giving properties, is a crucial task, a solution of which potentially provides a possibility to produce standardized beverages having fine and various tastes.